I'm debating between a 31cm and a 33cm Select S07 for my Futura 93l, sailing with a 5.8m F8 Ram.

The current fin I'm using is a Drake Freeslalom Swift 30cm

I've read somewhere that using too small a fin can impede on topend speed as the board sticks too much to the water and the Freeslalom Swift seems to be smaller than what other people are using. Can anyone comment on this?

With the Freeslalom Swift 30 I was getting some spinout, not too much, but had to be a bit careful with backfoot pressure.... I've read (in reviews) that Futuras are fastest when you really ride on the fin so is it possible that getting a slightly bigger fin might improve my topend speed?

I'm worried that with the 33cm I'll get overpowered too quickly...

Ideally before making my choice I would like to know if changing my Freeslalom Swift 30 to either one of the S07s will:

- improve my topend speed

- make my board plane faster

- make jibing more difficult

Any advice on which size to choose would be appreciated (as fins, like other windsurfing parts, don't come cheap and I want to make the best choice possible).